Thiophenylazobenzene: an alternative photoisomerization controlled by lone‐pair⋅⋅⋅π interaction

  • Azoheteroarene photoswitches have attracted attention due to their unique properties. We present the stationary photochromism and ultrafast photoisomerization mechanism of thiophenylazobenzene (TphAB). It demonstrates impressive fatigue resistance and photoisomerization efficiency, and shows favorably separated (E)‐ and (Z)‐isomer absorption bands, allowing for highly selective photoconversion. The (Z)‐isomer of TphAB adopts an unusual orthogonal geometry where the thiophenyl group is perfectly perpendicular to the phenyl group. This geometry is stabilized by a rare lone‐pair⋅⋅⋅π interaction between the S atom and the phenyl group. The photoisomerization of TphAB occurs on the sub‐ps to ps timescale and is governed by this interaction. Therefore, the adoption and disruption of the orthogonal geometry requires significant movement along the inversion reaction coordinates (CNN and NNC angles). Our results establish TphAB as an excellent photoswitch with versatile properties that expand the application possibilities of AB derivatives.

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Author:Chavdar SlavovORCiDGND, Chong Yang, Andreas Hans Heindl, Hermann A. Wegner, Andreas DreuwORCiDGND, Josef WachtveitlORCiDGND
Parent Title (German):Angewandte Chemie. International edition
Document Type:Article
Date of Publication (online):2019/10/09
Date of first Publication:2019/10/09
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2020/12/17
Tag:isomerization mechanisms; photochromism; photoswitches; thiophenylazobenzene; time-resolved spectroscopy
Page Number:8
First Page:380
Last Page:387
Institutes:Biochemie, Chemie und Pharmazie / Biochemie und Chemie
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 54 Chemie / 540 Chemie und zugeordnete Wissenschaften
Licence (German):License LogoCreative Commons - Namensnennung 4.0